Reflection high-energy electron diffraction: Difference between revisions

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The diffracted electrons interfere constructively at specific angles according to the crystal structure and spacing of the atoms at the sample surface and the wavelength of the incident electrons. Some of the electron waves created by constructive interference collide with the detector, creating specific diffraction patterns according to the surface features of the sample. Users characterize the crystallography of the sample surface through analysis of the diffraction patterns. Figure 2 shows a RHEED pattern.

[[File:TiO2 Good Surface.gif|thumbnail|400px|'''Figure 2'''. A RHEED pattern obtained from electron diffraction from a clean TiO2 (110) surface. The bright spots indicate where many electrons reach the detector. The lines that can be observed are Kikuchi Lines.]]

Two types of diffraction contribute to RHEED patterns. Some incident electrons undergo a single, elastic scattering event at the crystal surface, a process termed kinematic scattering.<ref name="ichimiya2004"/> Dynamic scattering occurs when electrons undergo multiple diffraction events in the crystal and lose some of their energy due to interactions with the sample.<ref name="ichimiya2004"/> Users extract non-qualitative data from the kinematically diffracted electrons. These electrons account for the high intensity spots or rings common to RHEED patterns. RHEED users also analyze dynamically scattered electrons with complex techniques and models to gather quantitative information from RHEED patterns.<ref name="braun1999"/>